Analysis of high-risk factors for severe Mycoplasma pneumoniae pneumonia associated with plastic bronchitis 

Background: Plastic bronchitis (PB) is a severe disease with rapid progression and high mortality, and its incidence is increasing. This study created and validated a diagnostic and predictive nomogram based on clinical characteristics to improve the diagnosis of PB in clinical practice. Methods: : This randomized, controlled, retrospective, observational study evaluated 447 children with severe Mycoplasma pneumoniae pneumonia, including 147 children with PB (intervention group) and 300 without PB (control group). Independent diagnostic predictors of PB were identified by multivariate logistic regression analysis and area under the receiver operating characteristic curve (AUC≥0.70), and a diagnostic model with six independent clinical characteristics was developed. The performance of the nomogram was assessed using the C-index, calibration curves, and decision curve analysis. Results: : Fever duration, neutrophil percentage, lactate dehydrogenase, procalcitonin, interleukin-6, and pleural effusion were independent risk factors for PB and were included in the nomogram. The C-index of the nomogram was 0.900 (95% CI: 0.866–0.934), indicating an excellent ability to discriminate between patients with and without PB. The calibration curve showed good agreement between the predicted and actual probability. The net reclassification improvement(NRI) was 0.1803 (95% CI: 0.0039–0.3567; p=0.0451), and the integrated discrimination improvement(IDI) was 0.1755 (95% CI: 0.1004–0.2505; p<0.001). Decision curve analysis(DCA) showed that the nomogram was clinically useful for detecting PB. Conclusions: : We constructed and validated a diagnostic and predictive nomogram with six independent risk factors for PB. The proposed nomogram can improve the early diagnosis of this complication in clinical practice.